Symptomatology and markers of anxiety disorders in Parkinson's disease: a cross-sectional study.

Anxiety is understudied in Parkinson's disease (PD), which is not justified by the prevalence and impact of anxiety disorders on quality of life in PD patients. In this cross-sectional study, 342 patients suffering from idiopathic PD underwent a research-based assessment including DSM IV criteria for anxiety disorders, the Hamilton anxiety rating scale (HARS) and the beck anxiety inventory (BAI). Thirty-four percent (34%) of subjects met the DSM IV criteria for at least one anxiety disorder; 11.8% met criteria for multiple anxiety disorders; and 11.4% had clinically relevant anxiety symptoms without meeting the criteria for any specific anxiety disorder. Score profiles on the HARS and BAI differed significantly between the disorders, but these differences were associated with different scores on a limited number of items, and the respective symptom profiles were not readily interpretable. Female sex, the presence of motor fluctuations, as well as a previous history of an anxiety disorder were markers for anxiety disorders. The use of a mono-amino oxidase (MAO)-B inhibitor was associated with a reduced prevalence of anxiety disorders. Research into anxiety in PD is hampered by the questionable validity of DSM IV defined anxiety disorders in this population. A first focus for research should therefore be the identification of clinically useful anxiety presentations and their validation in PD.